=Ptolemæ´us= First, called Ptolemy, surnamed Lagus. A king of Egypt, son of Arsinoe and Lagus. He was educated in the court of the king of Macedonia, and when Alexander invaded Asia Ptolemy attended him. After Alexander's death Ptolemy obtained the government of Egypt, where he gained the esteem of the people by acts of kindness. He made himself master of Phoenicia and Syria, and rendered assistance to the people of Rhodes against their enemies, for which he received the name of _Soter_. He laid the foundation of a library, which became the most celebrated in the world. He died in his eighty-fourth year, about 284 years B.C. He was succeeded by his son, Ptolemy Philadelphus, who showed himself to be a worthy successor of his father. His palace was an asylum for learned men, and he greatly increased the library his father had founded. Ptolemy Third succeeded his father Philadelphus on the Egyptian throne. He conquered Syria and Cilicia, and returned home laden with spoils. He was, like his predecessors, a patron of learning and the arts. Ptolemy Fourth, called Philopater, succeeded to the throne, his reign being marked by acts of cruelty and oppression. He died in his thirty-seventh year, after a reign of seventeen years, 204 years B.C. Numerous members of this celebrated family in succession occupied the throne, not, however, approaching to the greatness of the founders of the family. =Ptolemæ´us.= A celebrated geographer and astronomer in the reign of Adrian and Antoninus. He was a native of Alexandria, or, as some say, of Pelusium. In his system of the world, designated the Ptolemaic system, he places the earth in the center of the universe, which was generally received as correct till it was confuted by Copernicus. =Pyr´rhus.= A famous king of Epirus, son of Æacides and Phthia. He is celebrated for his military talents; and not only his friends, but his enemies, have been warm in extolling him. He is said to have had no superior in the art of war. He wrote several books on encampments and the ways of training an army. He fought against the Romans with much valor, and they passed encomiums on his great military skill. He was killed in an attack on Argos, by a tile thrown on his head from a housetop. =Pyr´rhus.= See NEOPTOLEMUS.